//
// Created by baoch on 2024/10/8.
//
#include<stdio.h>
int main()
{
    int score=0;
    scanf("%d",&score);
    int a = score;
    if(a>=90)
    {printf("A\n");}
    if(80 <= a && a <= 89)
    {printf("B\n");}
    if(70 <= a && a <= 79)
    {printf("C\n");}
    if(60 <= a && a <= 69)
    {printf("D\n");}
    if (0 <= a && a <= 59)
    {printf("E\n");}
    return 0;
}
